Beta PVP Arena! Let's feedback here~*

Here’s a brief write-up of the current Arena (Beta) system.
The Arena comes with 4 tabs: ATTACK, DEFENSE,RANKING & REWARDS.
We starts with 10 Sands of War(soW) and each battle cost 1 SoW.

ATTACK
10 random Arena opponents are shown here for your selection, list is refreshed hourly or at the cost of 10 Ironites.
You get to choose 1 Eddie & 3 allies for the battle, and you get to see your opponent characters without knowing their additional stats nor skill level.

DEFENSE
You get to list 1 Eddie & 3 allies as your defense team, and you get to test your own defense team without any cost nor reward.
You also get to see the player that defeated your team, and you get to revenge by starting a battle here.

RANKING
Shows the top 100 Arena players here, also get to see how are your Troopers doing.

REWARDS
Show the Ranking tiers & rewards and the amount of points to get them. There's is a countdown timer to indicate when will the ranking be reset.

There’s also an icon for Arena Shop which you get to redeem goodies with the Iron coins that you won, and also get to purchase SoW refill with 30 Ironites.

Are Iron Coins the only reward from a battle or do you also get gold/resources/XP?

I really like the option to attack players you defended against.

Does the AI seem to be the same as in PVE? Really need to think about the use of perfect hit triggered skills in the defense team if so.

Are there any differences in how the battle works compared to dungeons? For example, do you start with 6 power? Do you fight until a whole team is killed or just until either your or the opponents Eddie is killed?